Movable cutter for shaving apparatus

ABSTRACT

The reciprocable cutter of a dry shaver has substantially semicircular blades whose convex outer surfaces are adjacent to the inner side of the comb foil and whose side surfaces are provided with strips of diamond dust, sapphire dust or other finely comminuted granular material having a hardness which is considerably higher than the hardness of the ferrous or synthetic plastic material of the blades. The width of such strips is in the range of 1 millimeter and the granulae impart to the adjoining cutting edges of the blades an irregular (substantially undulate) shape to insure more reliable engagement between the cutting edges and the whiskers or hairs which penetrate through the apertures of the foil into the range of reciprocating blades. The outer surfaces of the blades are polished to a high degree of smoothness subsequent to application of granulae.

United States Patent [72] Inventor Werner Messinger Kronberg, 'lauuus, Germany [21] Appl. No. 819,050 [22] Filed Apr. 24, 1969 [45] Patented Aug. 10, 1971 I 73 Assignee Braun Aktiengesellschaft Franklurt am Main, Germany [32] Priority May 2, 1968 I 33] Germany [31] P17033305 54] MOVABLE CUTTER FOR SHAVING APPARATUS 8 Claims, 3 Drawing Figs.

[52] US. Cl 30/346.51, 30/346.-53

(51] Int. Cl B2611 19/06 [50] Field of Search 30/3465 1,

346.53, 346.54, 346.55, 350; 76/D1G. 8, D16. 12

[56] References Cited UNITED STATES PATENTS 2,108,797 2/1938 Comstock 30/346.54 X 2,900,719 8/1959 Kohneretal. 30/346.5l Xv 3,064,349 I 1/1962 Futterer et al. a 30/3465] X 3,263,328 8/1966 Craig 30/154653 X FOREIGN PATENTS 444,710 2/1968 Switzerland r. 30/346.53

Primary Examiner--Othell M. Simpson Attorney-Michael S. Striker ABSTRACT: The reciprocable cutter of a dry shaver has substantially semicircular blades whose convex outer surfaces are adjacent to the inner side of the comb foil and whose side surfaces are provided with strips of diamond dust, sapphire dust or other finely comminuted granular material having a hardness which is considerably higher than the hardness-of the ferrous or synthetic plastic material of the blades. The width of such strips is in the range of 1 millimeter and the granulae impart to the adjoining cutting edges ofthe blades an irregular (substantially undulate) shape to insure more reliable engagement between the cutting edges and the whiskers or hairs which penetrate through the apertures of the foil into the range of reciprocating blades. The outer surfaces of the blades are polished to a high degree of smoothness subsequent to application of granulae.

Patented Aug. 10, 1971 v 3,597,844

INVENTOR WEE/YER MESS IIVGEI? ATTORNEY BACKGROUND OF THEiNvsNTioN The present invention relates to improvements in shaving apparatus of the type commonly known as'dry shavers. More particularly, the invention'relates to improvements in cutters for use in such shaving apparatus. Still more particularly, the invention'relates to improvements in movable cutters serving to cooperate with the comb foils of dry shavers to: sever' whiskers or hairs which penetrate through the apertures of the v foil.

As a rule, the blades of movable cutters for use in dry shavers consist of hardened steel. Such blades are ground and polished to provide them with suitable cutting edges which sever whiskers or hairs while the movable cutter' reciprocates along the inner side of the apertured comb foil. A drawback of presently known movable cutters fordry shavers is'that the' cutting edges of their'blades become worn asa result of repeated frictional engagement with the inner side of the foil.

" throughthe apertures of the first cutter into the path of move- The wear results in rounding of cutting edges and develops even if the blades are made of highest qualitytsteelrProposalsto prolong the useful life of blades in movablec utters include the application of coats or liners of titanium carbide, boride or nitride. The thus coated blades are thereupon ground-to provide them with pairs of sharply defined cutting edges. It is also mentnof the blades. This distinguishes the improved blades fromconventional blades which are provided with uniform liners of hardened steel or titanium alloy. Such conventional liners =have smooth external surfaces so that they cannot enhance the gripping action of blades.

The outer surfaces of the blades are preferably polished to a high degree of smoothness subsequent to application of granulate to the adjoining side surface or surfaces.

The novel features which are considered as characteristic of the inventionare set forth in particular in the appended claims.

The improved'movable cutter itself, however, bothas to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed'description of certain specific embodiments with reference to the accompanyingdrawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a transverse sectional view of a movable cutter 1 which embodies the invention;

FIG; 2 is a fragmentary longitudinal sectional view of the -II-II or FIG. I; and

known to provide the blades with coatsof hard metal which are applied subsequent to grinding. All such proposals have met with relatively little success.

SUMMARY or THE INVENTION An object of the present invention is toprovide a shavingv apparatus with a novel arrangement of cutters, particularly to" provide the shaving apparatus with amovable cutter which can stand longer periods of use than presently known movable cutters and whose whisker-engaging or hair-engaging and severing action is superior to that of conventional movable cutters.

Another object of. the invention is to providea movable cutter which can be utilized in presentlyknown dry shavers.

A further object of the invention is to providea movable cutter which can be used in conjunction with'conventional comb foils.

An additional object of the'invention is to provide a novel method of treating the blades of movable cutters for'use in dry shavers.

Still another object of the invention is to provide a movable cutter with novel cutting edges.

an outer side and a preferably concave inner side, and a' second cutter which is movable in a predetermined direction with reference to the first cutter and comprises at least one but preferably a plurality of blades extending substantially or ex- FIG: 3 is a fragmentary plan view of the comb foil in a shaving head, further showing one cutting blade of the movable cutter.

DESCRIPTION OFTHE PREFERRED EMBODIMENTS FIGS .3! and2 illustrate a portion of a movable cutter MC which comprises a frame or carriage 2 and a plurality of thin parallel blades! which areinserted into and rigidly connected withthe'frame 2 and are located in planes extending at right angles to thedirection 'of reciprocatory movement of the cutter MCwith reference to'a stationary cutter 8 shown in FIG. 3. This'stationary cutter is a comb foil having a plurality of preferably circular apertures 7 (only one shown). The outer sideof'the foil 8 is guided along the face of the user and its concave innerside 4 (indicated in FIG. 2 by a broken line) is adjacent to the polished convex outer surfaces luof the blades I. Each of these blades has two side surfaces lb, Iv which flank the corresponding outer surface la and define therewith actlytransversely of the direction of movement. Each blade has a preferably convex outer surface which is adjacent to the inner side, of the first cutter and several (preferably two) side surfaces which flank the outer'surface and define therewith cutting edges. In accordance with a feature of my invention, at

sapphire dust or a substance of equivalent hardness, which are applied to the side surfaces lb, IL' in the region of the cutting edges Id, 1e. The granulae which form the strips 3 are preferably glued to the corresponding side surfaces lb, 11-; however, any'other suitable method of application can be resorted to as long as the granulae adhere to the blades 1 with a requisite force.

In order'to make sure that the granulae of strips 3 do not ex- .tend'outwardly beyond the outlines of the outer surfaces la,

such outcrsurfaces are preferably polished to a high degree of precisionfinish subsequent to formation of the strips 3. This insures that the granulae cannot cause excessive wear on the innerside 4=of the foil 8. Such polishing further insures the forwhose hardness substantially exceeds the harness of the (preferably ferrous or synthetic plastic) materialof the blades.

The granulae are preferably applied to each side surface of each blade and, preferably form thereon strips having awidthwhich need not exceed one-twentieth of an inch. Strips having a width of about I millimeter were found to be quite sa=tisfactory.

The granulae impart to the adjoining cutting rnation of sharply defined cutting edges which are of irregular (substantiallyu'ndulate)'shape, as shown at 5 in FIG. 3. This illustration: further shows a pair of whiskers or hairs 6 which extend inwardly throughthe aperture 7 of the foil 8 and into the range of blades I which reciprocate up and down, as viewed in FIG. 3. The whiskers'fi are severed along the edges of the surface surrounding the aperture 7 when the blade 1 shown in FIGS moves up and down. The irregular shape 5 of the cutting edges lo, Id insures thatthc whiskers cannot slide along the cutting edges while the blades I perform their reciprocatory movements with reference to the foil 8. Consequently, the whiskers 6 are severed as soon as they reach the adjoining portions of the cutting edges around the aperture 7.

The strips 3 not only prolong the useful life of blades I but also insure more satisfactory engagement between whiskers 6 and the cutting edges 1d, le. This is in contrast to the action of conventional movable cutters wherein the side surfaces of the blades are provided with smooth coats of hardened steel or titanium alloy Another important advantage of my cutter MC is that its blades 1 can be produced of a relatively soft metallic or synthetic plastic material. This is due to the fact that actual cutting edges are formed by the strips 3 (as at 5) so that the material ofthe blades 1 undergoes very little wear.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What l claim as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. In a shaving apparatus, a combination comprising a first cutter having an outer side and an inner side; and a second cutter movable in a predetermined direction with reference to said direction, said side surfaces being provided with granulae of a material whose hardness substantially exceeds the hardness of the material of said blade means, said granulae projecting from said side surfaces so as to impart to the adjoining cutting edge an irregular shape to insure a more reliable engagement between the cutting edges and the whiskers or hairs -to be cut by the shaving apparatus.

2. A combination as defined in claim I, wherein said granulae consist ofdiamond dust.

3. A combination as defined in claim I, wherein said granulac consist of sapphire dust.

4. A combination as defined in claim 1, wherein said granulae form on the respective side surface a strip which is adjacent to the outer surface and has a width of less than onetwentieth inch.

5. A combination as defined in claim 1, wherein said granulae impart to the adjoining cutting edge an undulatc shape.

6. A combination as defined in claim I, wherein said outer surface is polished to a high degree ofsmoothness.

7. A combination as defined in claim 1, wherein said first cutter is an apertured comb foil and said inner side thereof is of concave shape.

8. A combination as defined in claim 7, wherein said blade means includes a plurality of blades having a substantially semicircular outline. 

1. In a shaving apparatus, a combination comprising a first cutter having an outer side and an inner side; and a second cutter movable in a predetermined direction with reference to said first cutter, said second cutter comprising blade means having at least one outer surface adjacent to said inner side and side surfaces flanking said outer surface and defining therewith cutting edges extending substantially transversely of said direction, said side surfaces being provided with granulae of a material whose hardness substantially exceeds the hardness of the material of said blade means, said granulae projecting from said side surfaces so as to impart to the adjoining cutting edge an irregular shape to insure a more reliable engagement between the cutting edges and the whiskers or hairs to be cut by the shaving apparatus.
 2. A combination as defined in claim 1, wherein said granulae consist of diamond dust.
 3. A combination as defined in claim 1, wherein said granulae consist of sapphire dust.
 4. A combination as defined in claim 1, wherein said granulae form on the respective side surface a strip which is adjacent to the outer surface and has a width of less than one-twentieth inch.
 5. A combination as defined in claim 1, wherein said granulae impart to the adjoining cutting edge an undulate shape.
 6. A combination as defiNed in claim 1, wherein said outer surface is polished to a high degree of smoothness.
 7. A combination as defined in claim 1, wherein said first cutter is an apertured comb foil and said inner side thereof is of concave shape.
 8. A combination as defined in claim 7, wherein said blade means includes a plurality of blades having a substantially semicircular outline. 